THE KERGUELEN PLATEAU: MARINE ECOSYSTEM + FISHERIES Proceedings of the Second Symposium Kerguelen plateau Marine Ecosystems & Fisheries • SYMPOSIUM 2017 heardisland.antarctica.gov.au/research/kerguelen-plateau-symposium Shark by-catch observed in the bottom longline fishery off the Kerguelen Islands in 2006–2016, with a focus on the traveller lantern shark (Etmopterus viator) Charlotte Chazeau1, Samuel P. Iglésias2, Clara Péron1, Nicolas Gasco1, Alexis Martin1 and Guy Duhamel1 1 Muséum national d’Histoire naturelle, Département Adaptations du vivant, UMR 7208 BOREA (MNHN, CNRS, IRD, Sorbonne Université, UCBN), CP 26, 43 rue Cuvier, 75231 Paris Cedex 05, France 2 Institut Systématique Evolution Biodiversité (ISYEB), Muséum national d’Histoire naturelle, CNRS, Sorbonne Université, Station Marine de Concarneau, Place de la Croix, 29900 Concarneau, France Corresponding author:
[email protected] Abstract Data collected by fishery observers on board French fishing vessels targeting Patagonian toothfish (Dissostichus eleginoides), were examined to quantify and describe shark by-catch within the Kerguelen exclusive economic zone (EEZ). From 2006 to 2016, the fishing crews of longline vessels reported the total catches of the line and observers were asked to identify and count fish by-catch on 25% of the total fishing effort. A total of 26 203 longline hauls and more than 55 million hooks were checked by observers reporting 29 500 individual sharks caught as by-catch. Four shark species were identified (traveller lantern shark – Etmopterus viator, southern sleeper shark – Somniosus antarcticus, Portuguese dogfish – Centroscymnus coelolepis and porbeagle shark – Lamna nasus) among which E. viator was numerically largely dominant (99%). Relative abundance (number of shark per 1 000 hooks observed) calculated for sets with sharks present, was used to show bathymetric and geographical distributions and biological data were analysed.